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Message-ID: <20130928001404.25857.43349.stgit@birch.djwong.org> Date: Fri, 27 Sep 2013 17:14:04 -0700 From: "Darrick J. Wong" <darrick.wong@...cle.com> To: tytso@....edu, darrick.wong@...cle.com Cc: linux-ext4@...r.kernel.org, gnehzuil.liu@...il.com Subject: [PATCH 2/2] ext4: Spot-check block group sub-table locations Perform a quick sanity check of bitmap and inode table block numbers when loading them, and if there's something suspicious, mark the block group corrupt. Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com> --- fs/ext4/balloc.c | 7 +++++++ fs/ext4/ext4.h | 2 ++ fs/ext4/ialloc.c | 6 ++++++ fs/ext4/inode.c | 9 +++++++++ fs/ext4/super.c | 21 +++++++++++++++++++++ 5 files changed, 45 insertions(+) diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c index 6ea7b14..2f35689 100644 --- a/fs/ext4/balloc.c +++ b/fs/ext4/balloc.c @@ -396,13 +396,20 @@ ext4_read_block_bitmap_nowait(struct super_block *sb, ext4_group_t block_group) struct ext4_group_desc *desc; struct buffer_head *bh; ext4_fsblk_t bitmap_blk; + struct ext4_group_info *grp; desc = ext4_get_group_desc(sb, block_group, NULL); if (!desc) return NULL; bitmap_blk = ext4_block_bitmap(sb, desc); + if (!ext4_is_sane_bgdata_location(sb, block_group, bitmap_blk)) { + grp = ext4_get_group_info(sb, block_group); + set_bit(EXT4_GROUP_INFO_BBITMAP_CORRUPT_BIT, &grp->bb_state); + goto no_bitmap; + } bh = sb_getblk(sb, bitmap_blk); if (unlikely(!bh)) { +no_bitmap: ext4_error(sb, "Cannot get buffer for block bitmap - " "block_group = %u, block_bitmap = %llu", block_group, bitmap_blk); diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index af815ea..afb1bb2 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2531,6 +2531,8 @@ static inline void ext4_unlock_group(struct super_block *sb, spin_unlock(ext4_group_lock_ptr(sb, group)); } +int ext4_is_sane_bgdata_location(struct super_block *sb, ext4_group_t grp, + ext4_fsblk_t blk); /* * Block validity checking */ diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c index 137193f..4e7994b 100644 --- a/fs/ext4/ialloc.c +++ b/fs/ext4/ialloc.c @@ -122,8 +122,14 @@ ext4_read_inode_bitmap(struct super_block *sb, ext4_group_t block_group) return NULL; bitmap_blk = ext4_inode_bitmap(sb, desc); + if (!ext4_is_sane_bgdata_location(sb, block_group, bitmap_blk)) { + grp = ext4_get_group_info(sb, block_group); + set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state); + goto no_bitmap; + } bh = sb_getblk(sb, bitmap_blk); if (unlikely(!bh)) { +no_bitmap: ext4_error(sb, "Cannot read inode bitmap - " "block_group = %u, inode_bitmap = %llu", block_group, bitmap_blk); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 0d424d7..0a54e13 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3795,6 +3795,7 @@ static int __ext4_get_inode_loc(struct inode *inode, struct super_block *sb = inode->i_sb; ext4_fsblk_t block; int inodes_per_block, inode_offset; + struct ext4_group_info *grp; iloc->bh = NULL; if (!ext4_valid_inum(sb, inode->i_ino)) @@ -3814,6 +3815,14 @@ static int __ext4_get_inode_loc(struct inode *inode, block = ext4_inode_table(sb, gdp) + (inode_offset / inodes_per_block); iloc->offset = (inode_offset % inodes_per_block) * EXT4_INODE_SIZE(sb); + if (!ext4_is_sane_bgdata_location(sb, iloc->block_group, block)) { + grp = ext4_get_group_info(sb, iloc->block_group); + set_bit(EXT4_GROUP_INFO_IBITMAP_CORRUPT_BIT, &grp->bb_state); + ext4_error(sb, "Cannot read inode table - " + "block_group = %u, inode_table_block = %llu", + iloc->block_group, block); + return -EIO; + } bh = sb_getblk(sb, block); if (unlikely(!bh)) return -ENOMEM; diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 2c2e6cb..d22248e 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -2049,6 +2049,27 @@ void ext4_group_desc_csum_set(struct super_block *sb, __u32 block_group, gdp->bg_checksum = ext4_group_desc_csum(EXT4_SB(sb), block_group, gdp); } +/* returns 1 if the location of a blockgroup data item seems sane */ +int ext4_is_sane_bgdata_location(struct super_block *sb, ext4_group_t grp, + ext4_fsblk_t blk) +{ + struct ext4_sb_info *sbi = EXT4_SB(sb); + ext4_fsblk_t first_block = le32_to_cpu(sbi->s_es->s_first_data_block); + ext4_fsblk_t last_block; + + if (EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_FLEX_BG)) + last_block = ext4_blocks_count(sbi->s_es) - 1; + else { + first_block += grp * sbi->s_blocks_per_group; + last_block = first_block + (EXT4_BLOCKS_PER_GROUP(sb) - 1); + } + + if (last_block >= ext4_blocks_count(sbi->s_es)) + last_block = ext4_blocks_count(sbi->s_es) - 1; + + return blk >= first_block && blk <= last_block; +} + /* Called at mount-time, super-block is locked */ static int ext4_check_descriptors(struct super_block *sb, ext4_group_t *first_not_zeroed) -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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